In a variety of surgical procedures, it has become routine to utilize extracorporeal cardiopulmonary bypass in order to mechanically perform the functions normally conducted by the heart and lungs. Venous blood depleted in oxygen and rich in carbon dioxide is mechanically removed from the patient and pumped to oxygenating apparatus in order to oxygenate the blood and remove excess carbon dioxide. The blood is then returned to the patient's arterial system.
It is critical that adequate volumes of blood be drained from the patient during cardiopulmonary bypass so that the extracorporeal life support equipment can meet the patient's needs for oxygen and carbon dioxide removal. Serious tissue damage can result if insufficient quantities of oxygen are supplied to the patient. Further, acidosis may result from inadequate removal of carbon dioxide.
Various techniques and catheter designs have been used during extracorporeal treatment to provide venous drainage. In the past, femoral venous cannulation has been used as a backup procedure to other preferred procedures. In situations when preferred procedures for venous cannulation are especially difficult, femoral venous cannulation may be used. For example, venous cannulae may be especially difficult to pass when the patient is in the left thoracotomy position as for the repair of thoracic aneurysms, reoperative coronary artery bypass grafting, or left lung transplantation.
Consequently, there has been increasing use of femoral-femoral cardiopulmonary bypass in certain situations, emphasizing the need to be able to reliably obtain adequate venous drainage in a safe and rapid manner.
Heretofore, however, there have been serious drawbacks to femoral venous cannulation. Patient positioning and local anatomy may make passage of large venous cannulae difficult, if not impossible. In addition, forceful advancement of rigid cannula into the femoral or iliac veins may lead to disastrous complications such as vessel laceration.
Adequate venous drainage for cardiopulmonary bypass is often difficult to achieve via the femoral veins unless the venous cannula is positioned near the right atrium of the heart. This requires the cannula to travel a long distance from the venotomy to the right atrium of the heart. Frequently, guide wires that are used to direct the venous cannula into position are too thin and flexible to guide the cannula into the optimal position. Additionally, there is always the danger that the guide wire will lacerate the vein. An additional problem is that the passage of large cannulae through femoral and iliac veins is sometimes difficult because of the anatomy of the patient's venous system, previous surgery, calcified arteries and/or the sacral promontory.
Thus, it would be a substantial contribution to venous cannulation if an improved apparatus and method for effecting rapid femoral cannulation could be provided. It would be a further advance in the art if the apparatus could also be used to effect femoral arterial cannulation. The present invention provides such an apparatus and method.